This invention relates to folding apparatus, and more particularly, napkin folders to make product stacks having a two color sequence in each stack.
The invention is useful as applied to xe2x80x98dual folders, a well known face-to face arrangement of two single folders to double production of 1-ply semi-crepe napkins for consumer and commercial use.
Introduced in the 1940""s as a two wide machine with two delivery lanes, they were subsequently widened to three and four delivery lanes as paper machine widths increased.
Use of recycled fiber and wider webs dictated that most current folders are four wide for lowest cost production, but all prior art folders using two wide parent rolls deliver only one color stacks since the two wide parent roll webs are processed full width and slit just before they are longitudinally folded.
In current folders similar to the apparatus described in U.S. Patent of Small U.S. Pat. No. 4,349,185, parallel webs of the same color are advanced to adjacent folding plates as two separate but identical webs of the same color for transverse folding in each side of a dual follder before they are brought back together for delivery between belts as a supeposed pair of similarly colored napkins.
In the instant invention, parent rolls webs are slit into two product width webs before advancing to a turning and lane changing device where different colored webs are advanced to each pair of four coacting folding plates and transversly folded for delivery in four lanes.
The apparatus of this invention can produce two delivery lanes of alternatiely colored napkins from a two wide machine, a two color mixed stack and a single color stack from a three wide machine, or alternating colors in two or four lanes of a four wide machine
An objective of the invention is to achieve color mixing in stacks for a choice of unwind roll locations for the most efficient material handling of new supply rolls and delivered stacks.
Another object is to achieve color mixing utilizing current folder apparatus having only one knife-anvil roll pair cooperating with each single folder of the dual arrangement.
A further object is to describe apparatus to compensate for transverse web growth in each of two adjacent product webs being embossed with provision to deliver folded webs with equal panels from the longitudinal folding plates.
Other advantages and objects of the invention may be seen in the ensuing specification.